Waveguide Coupling With Continuous Carrier Plate And Cross-Shaped Element

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Solution Overview

Problem

Existing waveguide couplings for radar fill level measuring devices are mechanically sensitive and difficult to manufacture due to the need for precise milling of the carrier plate to expose the end of the feed line within the waveguide, which complicates the process and reduces stability.

Innovation Solution

A waveguide coupling design where the carrier plate extends continuously into the waveguide, featuring a cross-shaped coupling element with a longitudinal and transverse bar, and an electrically conductive shielding surface that is capacitively coupled to the feed line, simplifying the manufacturing process and enhancing electromagnetic adaptation by influencing the bandwidth around the desired center frequency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the carrier plate is milled to expose the end of the feed line within the waveguide, then the electromagnetic coupling is achieved, but the manufacturing complexity and mechanical sensitivity increase

Engineering Contradiction:
Improvemechanical stabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The feed line is pre-routed on the carrier plate before assembly, with its position and orientation predetermined. The coupling element is also pre-positioned on the carrier plate. This preliminary arrangement eliminates the need for complex post-assembly milling operations to expose the feed line end, while ensuring proper electromagnetic coupling geometry is achieved through the pre-planned structure.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The coupling element acts as an intermediary between the feed line and the waveguide interior. Instead of directly exposing the feed line end through complex milling, the coupling element mediates the electromagnetic energy transfer from the feed line into the waveguide, achieving the desired coupling effect through a simpler, more robust structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If the feed line end is exposed through precise milling, then electromagnetic coupling is achieved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvemilling precisionVSAvoidstructural complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The carrier plate integrates multiple functions: it supports the feed line, positions the coupling element, and provides structural support for the waveguide. By merging these elements into a unified structure where the feed line and coupling element are routed on the same plate, the design eliminates the need for separate precision milling operations to create exposed feed line ends, reducing both manufacturing precision requirements and structural complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If the coupling element is capacitively coupled to the feed line with shielding surfaces, then electromagnetic adaptation is improved, but the device complexity increases

Engineering Contradiction:
Improveelectromagnetic adaptationVSAvoidshielding structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Electrically conductive shielding surfaces are applied selectively in specific locations on the carrier plate rather than covering the entire structure. The shielding surfaces are positioned locally where needed to provide electromagnetic adaptation and control coupling characteristics, maintaining simplicity while achieving the desired electromagnetic performance.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The design achieves a bandwidth of approximately 20% of the carrier frequency, significantly improving upon conventional constructions, while maintaining mechanical stability and ease of manufacture by eliminating the need for precise milling and ensuring precise alignment of the feed line and shielding surfaces.

Implementation Method 1

the coupling element is capacitively coupled to the feed line

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentEP2506363B1Waveguide coupling
Publication Date: 2019.07.24 KROHNE MESSTECHNICK GMBH & CO KG
  • EP2506363B1 patent drawingFigure 1a~1b
  • EP2506363B1 patent drawingFigure 2a~2b
  • EP2506363B1 patent drawingFigure 3~4

AI summary

The waveguide coupling (1) has a waveguide (2) that is mounted at one side (5) of a support plate (3). The support plate is extended continuously in the inner region (6) of the waveguide. A feed line (4) is mounted on other side of support plate. An end (7) of feed line is protruded into the inner region of the waveguide. A coupling element (9) is provided to couple the feed line with waveguide.